High-Spatial-Resolution High-Temperature Sensor Based on Ultra-Short Fiber Bragg Gratings With Dual-Wavelength Differential Detection
| Autor: | Jun He, He Li, Baijie Xu, Shengzhen Lu, Yiping Wang, Gaixia Xu, Kuikui Guo, Xizhen Xu, Shen Liu |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Journal of Lightwave Technology. 40:2166-2172 |
| ISSN: | 1558-2213 0733-8724 |
| DOI: | 10.1109/jlt.2021.3131499 |
| Popis: | Type II fiber Bragg gratings (FBGs) inscribed with femtosecond (fs) laser possess significant potential for high temperature sensing. In this work, we propose and demonstrate a method for fabricating a parallel-integrated ultra-short type II FBG (PI-US-FBG) by using an fs laser point-by-point technology. The PI-US-FBG, featuring by an ultra-short grating length of 80 m, consists of six identical FBGs parallel-inscribed into a fiber core at different radial positions in the same cross section. The fabricated PI-US-FBG exhibits a broadband Gaussian-shape spectrum with a low reflectivity of ~10%, an ultra-low out-of-band insertion loss of 0.01 dB, and a large full width at half maximum bandwidth of 9.4 nm. Moreover, this PI-US-FBG could be used as a high temperature sensor with a wide measurement range from 25 to 1000 C, and an excellent linearity was achieved with a dual-wavelength differential detection. The temperature sensitivity could be increased from 0.00316 to 0.00945 (dB/C) by enlarging the wavelength spacing of the tunable laser. In addition, two cascaded PI-US-FBGs were used to precisely measure the temperature field distribution in a CO2 laser spot with a very high spatial resolution of 100 m. Hence, the proposed PI-US-FBGs could be used for a large-scale fiber sensor network, especially in future distributed temperature measurement with a high spatial resolution. |
| Databáze: | OpenAIRE |
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